Fuel feed device

ABSTRACT

A fuel supply system in which a fuel filter has a large filtration area is obtained without increasing an outer diameter of the fuel supply system and an outer diameter of a tank hole through which a pump module is inserted in a fuel tank. The fuel supply system comprises a fuel pump  5 , a fuel pressure regulator  9  for regulating pressure of fuel, and a fuel filter  6  having a hollow cylindrical filter case  7 for filtering the fuel, and in which the filter case  7  has a holding hole  7   a  for holding the fuel pump, a center line CL 1  of the holding hole is eccentric with respect to a center line CL 2  of the filter case  7  by a predetermined distance M, and a first enlarged space portion S 1  in which fuel system parts such as fuel pressure regulator  9  are accommodated is formed at a part surrounded by an outer circumferential portion of the fuel pump  5  and an outer circumferential portion of the filter case  7.

TECHNICAL FIELD

The present invention relates to a fuel supply system that is installedin a fuel tank of a vehicle or the like for raising a pressure of a fueland supplying the fuel to an injector injecting the fuel to an engine.

BACKGROUND ART

Hitherto, a system disclosed in the U.S. Pat. No. 5,392,750 is known asa fuel supply system for supplying fuel to an internal-combustionengine. Another fuel supply system as disclosed in the Japanese UtilityModel Publication (unexamined) No. 109465/1992 is also known. In theconstruction of these fuel supply systems, a hollow cylindrical fuelfilter is disposed on the outer circumference of a fuel pump, thusforming a fuel supply system.

However, in the construction disclosed in the U.S. Pat. No. 5,392,750and the Japanese Utility model Publication (unexamined) No. 109465/1992,the hollow cylindrical fuel filter occupies the outer circumferentialportion of the fuel pump. Accordingly, in order to form a pump module byuniting other fuel system parts, it is necessary for the fuel systemparts to be mounted on further outside in radial direction or mounted inaxial direction. Hence a problem exists in that volume of the entirepump module becomes large.

In the case of mounting the fuel system part on the outside in radialdirection, the pump module becomes large in outer circumferentialdiameter. Hence another problem exists in that a tank hole through whichthe pump module is inserted in the fuel tank needs to be large indiameter.

A further system disclosed in the International Publication No.WO96/23966 is also known as a conventional fuel supply system. A stillfurther system as disclosed in the Japanese Patent Publication(unexamined) No. 18932/1998is also known. In the construction of thefuel supply system disclosed in the No. WO96/23966, a C-shaped fuelfilter is mounted on an outer circumferential portion of the fuel pumpover approximately half of the circumference. Fuel system parts such asfuel level gauge are disposed in a space portion on the remaining sideof the outer circumferential portion of the fuel pump where the fuelfilter is not disposed, thus forming a the fuel supply system.

In the construction of the fuel supply system disclosed in the JapanesePatent Publication (unexamined) No. 18932/1998, a case for a fuel filterprovided with a C-shaped filtration element inside thereof is D-shapedin section. Fuel system parts such as sensor for a fuel level gauge aredisposed in the portion formed by cutting a cylindrical member, thusforming a fuel supply system.

However, in the construction of the fuel supply systems disclosed inboth No. WO96/23966 and Japanese Patent Publication (unexamined) No.18932/1998, since the filtration element of the fuel filter is C-shaped,a problem exists in that the area for filtering the fuel is small ascompared with a system having a hollow cylindrical fuel filter.

The present invention was made to solve the above-discussed problems andhas an object of obtaining a fuel supply system in which the filtrationarea of the fuel filter is increased without enlarging outer diameter ofthe fuel supply system and outer diameter of a tank hole through which apump module is inserted in the fuel tank.

DISCLOSURE OF INVENTION

A fuel supply system according to the invention comprises a fuel pumpinstalled in a fuel tank for raising a pressure of a fuel and supplyingthe fuel to an injector of an internal-combustion engine, a fuelpressure regulator for discharging a surplus of the fuel discharged fromthe fuel pump as a surplus fuel from a fuel passage into the fuel tankand regulating the pressure of the fuel, and a fuel filter having ahollow cylindrical filter case in which a filtration element forfiltering the fuel discharged from the fuel pump is accommodated,wherein the filter case is provided with a holding hole for holding thefuel pump, a center line of the holding hole is formed eccentric withrespect to a center line of the filter case by a predetermined distance,and a first enlarged space portion is formed at a part surrounded by anouter circumferential portion of the fuel pump and an outercircumferential portion of the filter case.

Fuel system parts such as fuel pressure regulator are accommodated inthe first enlarged space portion.

A second enlarged space portion for accommodating a lead wire of a fuellevel gauge is formed between an inner circumferential wall of thefilter case and the outer circumferential portion of the fuel pump.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional side view of a fuel supply system showing anembodiment of the invention.

FIG. 2 is a plan view of the fuel supply system in FIG. 1.

FIG. 3 is a sectional view taken along the line III—III in FIG. 1.

FIG. 4 is a sectional view taken along the line IV—IV in FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

The present invention is hereinafter described in more detail withreference to the accompanying drawings.

FIG. 1 is a sectional side view of a fuel supply system showing anembodiment of the invention. In the drawing, reference numeral 100 is afuel supply system, numeral 1 is a fuel tank, and numeral 2 is anopening of the fuel tank 1. Numeral 3 is a flange made of anelectrically insulating synthetic resin, and the flange 3 has a lid 3 afor covering the opening 2 of the fuel tank 1 and a discharge pipe 3 b.Numeral 4 is a gasket for hermetically sealing a space between the fueltank 1 and the lid 3 a in order to prevent leakage of fuel. Numeral 5 isa fuel pump for supplying the fuel to an injector of aninternal-combustion engine in a pressurized manner, and the fuel pump 5has an intake port 5 a and a discharge port 5 b.

Numeral 6 is a fuel filter for filtering the fuel discharged from, thefuel pump 5, and in which a chrysanthemum-shaped filtration element 8 isaccommodated in a filter case 7 formed into a hollow cylinder made of asynthetic resin. The filter case 7 has a pump holding hole 7 a forholding an outer circumferential portion of the fuel pump 5, acylindrical inner circumferential wall 7 b for accommodating thefiltration element 8, and a regulator holding hole 7 c for mounting afuel pressure regulator 9 for regulating the pressure of the fueldischarged from the fuel pump 5. The filtration element 8 is held by afilter holder 8 a made of a synthetic resin. As shown in FIGS. 1 and 4,a center line CL1 of the pump holding hole 7 a is eccentric with respectto a center line CL2 of the hollow cylindrical filter case 7 by apredetermined distance M. A first enlarged space portion S1 is formed ata part surrounded by an outer circumferential portion of the filter case7 and an outer circumferential portion of the fuel pump 5. The fuelpressure regulator 9 discharges a surplus of the fuel discharged fromthe fuel pump 5 as surplus fuel out of a fuel passage into the fuel tank1 and regulates the pressure of the fuel, and is disposed in the firstenlarged space portion S1.

Numeral 10 is a filter cover made of a synthetic resin and provided witha first fuel passage 10 a for delivering the fuel discharged from thedischarge port 5 b of the fuel pump 5 to the fuel filter 6, and a valvehole 10 b. A check valve 11 is built in the valve hole 10 b. Numeral 12is a pump holder made of a synthetic resin, and the pump holder 12 holdsthe fuel pump 5 through a cushion rubber 13. Numeral 14 is an intakefilter that is connected to an intake port 12 a formed on the pumpholder 12 and filters foreign matter such as iron powder when the fuelin the fuel tank 2 is sucked into the fuel pump 5. Numeral 15 is a fuellevel gauge. A gauge holding portion 12 b is formed on the pump holder12 utilizing the first enlarged space portion S1, and the fuel levelgauge 15 is held by this gauge holding portion 12 b. Numeral 16 is aconnector by which a lead wire (not shown) for supplying a power to thefuel pump 5 and a lead wire 15 a for supplying a power to the fuel levelgauge 15 are connected. Numeral 17 is a cut-off valve, and numeral 18 isa breather pipe. These fuel system parts are integrally formed into onebody in the form of a pump module, and are suspended at the opening 2 ofthe fuel tank 1 through the gasket 4.

Operation of the fuel supply system 100 constructed as described aboveis hereinafter described.

When driving the fuel pump 5, the fuel in the fuel tank 1 is sucked intothe fuel pump 5 through the intake filter 14. Thereafter the fuel isdischarged from the discharge pipe 5 b, flows through the first fuelpassage 10 a in the direction indicated by the arrow A, and entersbetween an outside of the filtration element 8 and the filter case 7.The fuel then passes through the filtration element 8 as indicated bythe arrow B, whereby dust and the like in the fuel are filtered. Thenthe filtered fuel flows in the direction indicated by the arrow C, opensthe check valve 11 and flows in the direction indicated by the arrow D,and is supplied through the discharge pipe 3 b to an injector of a fuelinjection system installed in an engine not shown.

In the meantime, a part of the fuel that has flown in between theoutside of the filtration element 8 and the filter case 7 flows in thedirection indicated by the arrow E, and enters in the fuel pressureregulator 9, where the pressure of the fuel is regulated. Then, the fuelflows in the direction indicated by the arrow F as a surplus fuel and isdischarged into the fuel tank 1.

In this Embodiment 1 of above-described construction, the hollowcylindrical fuel filter 6 is used in the filtration element 8, and thecenter line CL1 of the pump holding hole 7 a is eccentric with respectto the center line CL2 of the hollow cylindrical filter case 7 by apredetermined distance M. Therefore, it is possible to form the firstenlarged space portion S1 at the part surrounded by the outercircumferential portion of the filter case 7 and the outercircumferential portion of the fuel pump 5, and to accommodate the fuelsystem parts such as the fuel pressure regulator 9, the fuel level gauge15, etc. in the first enlarged space portion S1. Consequently, it is notnecessary to increase the outer diameter of the fuel supply system 100and the diameter of the tank hole through which the pump module isinserted in the fuel tank 1, and it is therefore possible to obtain afuel supply system in which the fuel filter 6 has a large filtrationarea.

The second enlarged space portion S2 is formed between the cylindricalinner circumferential wall 7 b of the filter case 7 and the outercircumferential portion of the fuel pump 5, and the lead wire 15 a ofthe fuel level gauge 15 is accommodated in the second enlarged spaceportion S2 accommodates. Consequently, it is possible to protect thelead wire 15 a by the inner circumferential wall 7 b of the filter case7 made of a synthetic resin, and prevent the lead wire 15 a from beingdamaged at the time of mounting it on the fuel tank 1.

Industrial Applicability

As described above, the fuel supply system according to the inventioncomprises a fuel pump installed in a fuel tank for raising a pressure ofa fuel and supplying the fuel to an injector of an internal-combustionengine, a fuel pressure regulator for discharging a surplus of the fueldischarged from the fuel pump as a surplus fuel from a fuel passage intothe fuel tank and regulating the pressure of the fuel, and a fuel filterhaving a hollow cylindrical filter case in which a filtration elementfor filtering the fuel discharged from the fuel pump is accommodated,wherein the filter case is provided with a holding hole for holding thefuel pump, a center line of the holding hole is formed eccentric withrespect to a center line of the filter case by a predetermined distance,and a first enlarged space portion is formed at a part surrounded by anouter circumferential portion of the fuel pump and an outercircumferential portion of the filter case. As a result, the fuel systemparts such as fuel pressure regulator, fuel level gauge or the like areaccommodated in the first enlarged space portion, and it is notnecessary to increase the outer diameter of the fuel supply system andthe outer diameter of the tank hole through which the pump module isinserted in the fuel tank. It is therefore possible to obtain a fuelsupply system in which the fuel filter has a large filtration area.

The second enlarged space portion, in which the lead wire of the fuellevel gauge is accommodated, is formed between the inner circumferentialwall of the filter case and the outer circumferential portion of thefuel pump. Consequently, the lead wire of the fuel level gauge isprotected by the filter case and is prevented from being damaged at thetime of mounting it on the fuel tank.

What is claimed is:
 1. A fuel supply system comprising: a fuel pumpinstalled in a fuel tank for raising a pressure of a fuel and supplyingthe fuel to an injector of an internal-combustion engine; a fuelpressure regulator for discharging a surplus of the fuel discharged fromsaid fuel pump as a surplus fuel from a fuel passage into said fuel tankand regulating the pressure of the fuel; and a fuel filter having ahollow cylindrical filter case in which a filtration element forfiltering the fuel discharged from said fuel pump is accommodated;wherein said filter case is provided with a holding hole for holdingsaid fuel pump, a center line of said holding hole is formed eccentricwith respect to a center line of said filter case by a predetermineddistance, and a first enlarged space portion is formed at a partsurrounded by an outer circumferential portion of said fuel pump and anouter circumferential portion of said filter case.
 2. The fuel supplysystem according to claim 1, wherein fuel system parts such as fuelpressure regulator are accommodated in the first enlarged space portion.3. The fuel supply system according to claim 1, wherein a secondenlarged space portion for accommodating a lead wire of a fuel levelgauge is formed between an inner circumferential wall of the filter caseand the outer circumferential portion of the fuel pump.